Electric circuit interrupter



Patented July 22, 1941 ELECTRIC CIRCUIT INTEERUPTER Benjamin It.Hermann, Lanesborough, Mass., assignor to General Electric Company, acorporation of New York Application August 31, 1939, Serial No. 292,852

11 Claims.

The present invention relates to electric circuit interrupters, and moreparticularly to circuit in-- terrupters, such as, for example, drop-outfuse cutouts, which incorporate a movably mounted switching unitin'cluding an insulating holder for supporting an automatically operablecircuit interrupting means, together with mechanism capable offunctioning automatically upon operation of the circuit interruptingmeans to effect movement of an element or elements of the switching unitfrom an operative position to a dropped-out position or other positiongiving indication of circuit interruption.

The invention has for one of its objects the provision, in a circuitinterrupter such as referred to above, of improved construction andarrangement of supporting and latching mechanism whereby release of theswitching unit from an operative position upon operation of the circuitinterrupting means is efiected without the neces sity for movement ofthe insulating-holder of the switching unit.

.Another object is the provision, in a drop-out circuit interrupter ofthe enclosed type, of improved mechanism whereby release of theswitching unit" from operative position upon operation of the circuitinterrupting means is effected in response to movement of acover or doorof the casing of the circuit interrupter, and independently of movementof the insulating holder forming part of the switching unit.

A further object of the invention is the provision of improved contactmechanism particularly applicable to drop-out circuit interrupters butnot necessarily limited to such application.

The invention has for an object also the provision of improved apparatusfor carrying out certain features of the invention disclosed and morebroadly claimed in United States Letters Patent 2,197,646, granted April16, 1940, upon an application of George F. Lincks and assigned to thesame assignee, as the present invention.

Other objects and the details of that which I consider to be novel andmy present invention will become apparent from the following descriptionand the claims appended thereto, taken in conjunction with theaccompanying drawing wherein are shown exemplary embodiments of myinvention as applied to fuse cutouts of the enclosed drop-out type. i

In the drawing, Fig. 11s a side elevation, partially in sectionj'of anexemplary forth of fuse cutout incorporating one embodiment of my.invention, the parts being shown in normal operative positions; Fig. 2is a partial view of the cutout of Fig. 1, showing the parts thereofafter circuit interrupting operation; Fig. 3 is. a sectional plan viewalong the line 3-3 of Fig. 1; Fig. 4

a is a detail view of a part of the mechanism of Fig. 1; Fig. 5 is aside elevation, partially in section of a fuse cutout incorporating asecond embodiment ofmy invention, with the parts in normal operativepositions; and Figs. 6, '1, and 8 are detail/views of a modified form'oflatching and contact making mechanism suitable for carrying out myinvention. I

The cutout shown in Figs. 1-4 of the drawing, has 'a casing III which isconstructed of porcelain, glass, or other suitable insulating materialand which has an integrally formed electric creepage and gas barrier onthe inner rear A wall thereof. The casing is provided with a rearwardlyextending mounting bar i2 for attachment to an electric line pole andcross-arm structure, or other suitable supportlng'means. Terminals l3and I4 are attached on the inner rear, wall of the casing respectivelyabove and below barrier II and are provided with suitable clampingmeans, indicated at l5, for attachment of line conductors or leadsthereto. Upper terminal I! has a generally U-shaped contact clip It, theresilient arms of which extend in spaced substantially parallelrelationship toward the front of casing III, as will be seen best fromFig. 3. The

lower terminal I4 has a similar U-shaped contact Pivotally supportedwithin casing III is a switching unit which comprises in the main anelongated tubular holder 20, a hinge element 2|, 9. cover or door 22 forthe open front of the casing, and contact and latching mechanism whichwill be described in detail hereinafter. Holder 20, which is constructedof fibrous or other suitable insulating material, is open at the lowerend for expulsion of gases therefrom and is closed at the upper end by aremovable terminal cap 23.

1 This holder serves to accommodate in a well known manner a circuitinterrupting element in the form of afuse link, the upper end of whichlink is electrically connected with cap 23, and the lower end or cableextension 24 of which link extends out of the lower end of the holder.

Hinge element 2| has a socket in which the lower end of holder 20 isfixedly secured by means of a screw 25 or other suitable means, and thehinge element has a hook portion 26 engageable with ahinge bracket 21 onthe casing for pivotally supporting the switching unit. A resilient 1finger ll is attached to the top of the hinge element by means of ascrew II, and the free end of this flngeris arranged to bearagainst thetop of hinge bracket 21 in a manner tending to effect rotation of theswitching unit to open position. Cover 22 is of insulation material andhas, on the outside thereof, an eyelet handle 32 for manipulation of theswitching unit to and from operative position. On the inner side of thecover is a projection 33 having an opening in which holder 25 is fixedlysecured by means of screws 34. Thus. in the embodiment of Fig. 1, thehinge element, holder and cover form a rigid switching unit.

The exemplary switching unit shown on the drawing has two combinedcontact making and latching mechanisms, the upper one of which issupported on terminal cap 23 of holder 20 and the lower one of which issupported on a terminal ferrule 35 fixedly mounted intermediate the endsof the holder. If desired, the upper mechanism also may be supported ona terminal ferrule which is fixedly mounted on the holder and to whichthe cap 23 is removably secured. The two mechanisms are identical inform so that a description of the upper one, shown in detail in Fig. 3,will suflice to give an understanding of the construction of bothmechanisms. On the rear of cap 23 there is secured a plate 35 having arearwardly extending projection 51 which supports a vertical pivot pin38. Two contact engaging elements 39 are pivotally mounted on pin 38.The parts of elements 39 which extend forwardly from the pivot point aredisposed respectively on opposite sides of cap 23 and have contactportions 45 arranged for engagement respectively with the inner surfacesof the arms of upper contact clip 15. The extreme forward ends ofelements 35 are bent inwardly and provided with pins ll upon which arerotatably mounted rollers 42. Elements cross each other at their pivotpoint, in the manner of a tongs, and the rearwardly extending arms 42 ofthe elements have a tension spring ll connected therebetween. As will beevident from the drawing, this spring biases elements I! for movement ofthe contact portions 40 thereof relatively toward each other and out ofengagement with the arms of contact clip l5.

For controlling the positioning of the elements 35 of both the upper andlower contact and latching mechanisms, a slide member 41, of insulationmaterial, is mounted on the inner face of cover 22, as shown in Fig.4.This slide member passes through a slot 48 in door projection 52, andhas longitudinal slots 45 engaging screws 55 on the cover. Thus, theslide member is guided for vertical movement on the cover, and twotension springs 51, respectively connected between ears 52 on the slidemember and screws 34 on door projection 35, are provided for biasing theslide member downwardly. The upper end of the slide member has awedgeshaped portion 54 which tapers upwardly and which passes betweenthe rollers 42 of the upper contact and latching mechanism. A similarwedge-shaped portion 55, intermediate the ends of the slide member,passes between the rollers 42 of the lower contact and latchingmechanism. A finger 55 is attached to the lower end of the slide member.Normally the slide member is held releasably in its upper position,shown in Figs. 1 and 4, by the fuse link in holder 25, the cableextension 2| of which fuse link is looped under finger 55 and clamped toa depending lug 51 on holder terminal 55.

when slide member 41 is in its upper position, wedge portion 54'maintains the contact portions ll of upper contact enga ing elements I!relav tively spread apart in firm engagement respectively with the armsof upper contact clip It, as shown in Fig. 3. Similarly, wedge portion55 maintains the contact portions of lower contact engaging elements 25relatively spread apart in firm engagement with the arms of lowercontact clip l1. Under these circumstances, the arms of contact clips I5and I1 act as latch detents, and the frictional engagement between thesedetents and the contact portions 45 of elements 25 is sumcient tomaintain the switching unit rele'asably in its operative position shownin F18. 1.

Upon rupture of the fuse link in holder 20, due to overload orshort-circuit, slide member 41 is released and moves downwardly underthe influence of springs 5|, The downward movement oi the slide memberpermits the contact portions of the elements 39 of each of the contactmaking mechanisms, to move relatively toward each other, under theinfluence of the corresponding one of the biasing springs 54, and out oflatching engagement with the arms of the corresponding stationarycontact clip. When the latching engagement is released, spring 50becomes efiective to initiate outward swinging of the switching unit andthe switching unit finally swings to its dropped-out position, partiallyshown in Pig. 2, under the influence of gravity. The switching unit,when inopen position, may be removed readily from casing ID bydisengagement of hook 25 of hinge element 2| from hinge bracket 21. Witha new fuse link installed in the holder, the cable extension of the fuselink is hooked under finger and secured to terminal lug 51 in the mannerpreviously described, so as releasably to hold the slide member in itsupper position'to maintain contact engaging elements '55 in spread apartpositions. Then, upon engagement of hook 25 with bracket 21, theswitching unit may be swung into operative position in the manner of acommon switch blade.

The embodiment shown in Fig. 5 differs from the embodiment justdescribed, principally in that the casing cover 55 is slidably mountedon fuse holder 25 and has wedges 59 and 55, corresponding respectivelyto wedges 54 and 55 of the first embodiment, fixedly mounted on theinner side of the cover. For support of the cover on the fuse holder,there are provided on the inner side of the cover, and in verticallyspaced relationship, two projections 51 having openings 52 for'slidablyreceiving the holder. A further minor difference in the construction ofFig. 5, over that of Fig. 1, is that the lower stationary terminal 53and contact clip 55, corresponding respectively to the lower terminal I4and contact clip l1 of the first embodiment, are mountedat a lower pointon the rear wall of the casing in order not to interfere with downwardsliding of the cover relative to the holder. The operation or the cutoutof Fig. 5, upon rupture of the fuse link in the holder, is the same asthat previously described in connection with the cutout of Fig. 1, withthe exception that cover 58 slides bodily down so as to cause the wedges59 and 55 to release the contact engaging elements 39 for inwardretraction of the latter relative to each other and out of latchingengagement with the arms of the stationary contact clips l5 and 54.

Figs. 5, 'l, and 8 show details of a modified.

form of contact making and latching mechanism which may be employedeither at the upper or lower terminal of a cutout such as shownmechanism. The stationary contact shown in Fig. 6 is adapted to bemounted upon a cutout casing or other insulating support of a circuitinterrupter, and comprises a mounting plate 65 having a U-shaped contactclip 66 and a U-shaped resilient backing clip 81 secured thereto bymeans of screws 68. Adjacent the outer-ends of the contact arms of clip66, thereare formed inwardly extending detent projections 88; and theextreme outer ends of the arms of clip 88 are flared outwardly toprovide guide portions 10. Any suitable form of terminal structure maybe employed for supporting the contact making and latching mechanismshown in Fig. 6. In the illustrated embodiment, the terminal structurecomprises a metallic collar 1| mounted on an insulating fuse holder,indicated at 20, and having a rearwardly extending projection 12. Thebase of a U- shaped contact clip 13 is secured to projection 12 in sucha manner that the arms 14 of this clip extend forwardly in spacedrelationship and respectively on opposite sides of terminal collar H andholder 20. Adjacent the outer ends of arms 14 are formed latching seatsI5 for cooperation respectively with detent projections 69 of contactclip 86. The extreme outer ends of arms 14 have forwardly extending lugs16 for a purpose to be described.

The essential details of the modified spreader mechanism will beapparent from Figs. 7 and 8. This spreader mechanism includes aninsulating slide member, inclusively designated 1'! in Figs. '1 and 8,which may be slidably supported on the cover of a cutout casing in amanner similar to the slide member in the embodiment of Fig. 1, or whichmay be slidably mounted in any suitable manner directly on theinsulating holder 20 in case the herein described mechanism is employedin an open type circuit interrupter. Slide member 11 is made up of twoparallel bars 18 which are constructed of insulation material and theends of which are seen in Fig. 6. One or more pivot pins 19 aresupported by and extend between these bars. Only one pivot pin, disposedat the end of member 11, is shown in the drawing, but it is to beunderstood that another such pivot pin may be disposed intermediate theends of the slide member in case two contact making and latchingmechanisms are employed as in the cutouts of Figs. 1 and 5. The spreadermechanism includes also two spreader arms 80 which are pivotally mountedat one end on pin 19, and which extend in opposite directions from thepivot pin. The outer ends of these arms have bearing openings 8|pivotally engaging the lugs 16 respectively on arms 14 of contact clipI3.

when member 11 is held in its upper position indicated in Fig. '7, as bymeans of a fuse link as in the embodiment of Fig. 1, arms 80 areoperative to maintain the arms 14 of contact clip 13 spread apartinlatching engagement with the arms of contact clip 66, as shown in Fig.6. Under these circumstances, latching seats are in engagement withdetent projections 69 to restrain the fuse holdr in an operativeposition, and a very good electric connection is provided betweenterminal H and the stationary terminal which includes contact clip 66.Member 11 may be arranged to move automatically downwardly under theinfluence of gravity. or may be biased downwardly by means of springs asin the embodiment of Fig. 1, upon release of the member due to circuitinterrupting operation. such downward movement of member 11 causes armsII to retract clip arms ll relatively toward each other and out ofengagement with the arms of contact clip it If desired, clip arms 14 maybe resiliently biased in such manner that they tend naturally to movetoward each other upon being released by the spreader mechanism. Fromthe foregoing it will be evident that one of the important features ofmy present invention is the securing, in a circuit interrupter of thedrop-out type, of a highly eflicient conductive connection between thestationary contacts and the terminals of the movable switching unit,while rendering movement of the in-- sulating holder of the switchingunit unnecessary to effect automatic release of the switching unit fromoperative position.

The constructions herein described and illustrated are intendedto beexemplary only, it being contemplated that there will suggest themselvesto those skilled in the art other applications of certain features ofthe invention and other modiilcations of the illustrated structures. Forexample, with some forms of circuit interrupters, it may be desired todispense with eitherthe upper or the lower of the combined contactmaking and latching mechanisms and to employ some other means foreffecting electric connection between the corresponding stationary con-'tact and switching unit terminal. Hence, it is intended that such othermodifications and applications as do not depart from the'true spirit orthe present invention shall come within the scope of the appendedclaims.

What I claim as new and desire to secure by Letters Patent of the UnitedStates is:

1. In a circuit interrupter, a support having spaced terminals, aswitching unit for connection between said terminals includinga tubularfuse holder pivoted adjacent one end on said support and a fuse link insaid holder, a pair of elements associated with the holder at a pointremote from said one end of the holder for engagement with cooperativestructure on said support to latch the holder in connected position,said elements being guided for relative movement toward and away fromeach other, and positioning mechanism for said elements having a partextending along the side of said holder and automatically movable fromone position to another position relative to the holder upon rupture ofsaid fuse link, said mechanism maintaining said elements in latchingengagement with said structure when saidpart is in said one position andeifecting movement of the elements in opposite directions to release theelements from said structure upon movement of said part to said'otherposition, saidpart being releasably restrained in said one position byengagement witha portion of said fuse link which extends out of saidpivoted end of said holder.

2 In a circuit interrupter, a support, a fuse holder pivoted adjacentits lower end on said sup ort and having spaced terminals forcooperation with spaced terminals on the support, a

fuse link in said holder connected between said holder terminals andhaving a portion extending out of the lower end of the holder, at leastone of said holder terminals being located a substantial distance abovethe lower end of the'holder, said one terminal having two contactelements supported for relative movement toward and away from each otherand arranged for engagement with cooperative contact structure on saidsupport, and positioning mechanism for said elements operable tomaintain the elements in firm engagement with said structure andoperable alternatively to eifect movement of the elements in oppositedirections so as to release the elements from said structure, saidmechanism having a part extending along side of said holder and movablerelative to the holder, which said part is engaged by said outwardlyextending portion of the fuse link so as to prevent said alternativeoperation of said mechanism while the fuse link is intact.

3. In a circuit interrupter, a support, a fuse holder pivoted adjacentone end on said support, said holder having a fuse link therein and aterminal located a substantial distance from said one end of the holder,said terminal having a pair of relatively spreadable contact elements, aterminal on said support having a pair of spaced opposed contactsurfaces adapted to receive said spreadable elements therebetween, amember extending in substantially parallel side by side relation withsaid holder and longitudinally movable relative to the holder, a part ofsaid member extending adjacent said pivoted end of the holder, a portionof said fuse link extending out of said end of the holder and engagedwith said part so as to restrain said member in one position relative tothe holder, said member being automatically movable to a second positionrelative to the holder upon rupture of said fuse link, means associatedwith said member to spread said contact elements apart when the memberis in said one position, and means to eifect movement or" said elementsrelatively toward each other upon movement of said member to said secondposition.

4. In a circuit interrupter, a support, a fuse holder movably mountedthereon, a fuse link in said holder having a portion extending out ofone end of the holder, 9. contact intermediate the ends of the holder ata substantial distance from said one end of the holder and comprisingtwo elements arranged to engage a cooperative contact on said support,said elements being supported for relative movement toward and away fromeach other, and mechanism operable to maintain said elements in firmengagement with said cooperative contact and operable alternatively toeilect movement of the elements in opposite directions so as to releasethe elements from said cooperative contact, said mechanism including amember extending in side by side relation with said holder andautomatically movable from one position to another position relative tothe holder upon rupture of said fuse link, a part of said memberextending adjacent said one end of the holder and being interconnectedwith said outwardly extending fuse link portion so as releasably torestrain said member in its said one position, another part of saidmember extending adjacent said contact and having means associatedtherewith for rendering the relative positions of said elementsdependent upon the position of said member.

5. In a circuit interrupter, a support, a fuse holder movably mountedthereon, a fuse link in said holder having a portion extending out ofone end of the holder, a contact on the other end of the holdercomprising two elements arranged for engagement with a cooperativecontact on said support, said elements being supported for relativemovement toward and away from each other, and mechanism operable tomaintain said elements in firm engagement with said cooperative contactand operable alternatively to elect movement of said elements inopposite directions so as to release the elements from said cooperativecontact, said mechanism including a member extending in side by siderelation with said holder and automatically movable from one position toanother position relative to the holder upon rupture of said fuse link,a part of said member extending adjacent said one end of the holder andbeing interconnected with said outwardly extending fuse link portion soas releasably to restrain said member in said one position, another partof said member extending adjacent said other end of the holder 'andhaving means associated therewith for rendering the relative positionsof said contact elements dependent upon the position of said memher.

6. In a circuit interrupter, a support, a fuse holder having spacedterminals for cooperation with spaced terminals on said support, a fuselink in said holder connected between said holder terminals, each ofsaid holder terminals having a pair of contact elements for engagementwith a contact structure forming part of the corresponding terminal onsaid support, the two elements of each of said pairs being supported forrelative movement toward and away from each other, and mechanismoperative to maintain said pairs of elements in firm engagement eachwith the corresponding one of said contact structures, said mechanismbeing operable alternatively to effect movement of the elements of eachof said pairs in opposite directions so as to release said pairs ofelements from said contact structures, said mechanism including a memberexi-ending in side by side relation with said holder and automaticallymovable from one position to another position relative to the holderupon rupture of said fuse link, said member having means associatedtherewith respectively adjacent each of said pairs of elements forrendering the relative positions of the elements of the respective pairsin an electric cutout or like casing having spaced terminals; saiddevice comprising in combination, a cover for an open side of anelectric cutout or like casing, an insulating holder for supporting anautomatically operable circuit interrupting means and having spacedterminals for cooperation respectively with spaced terminals in anelectric cutout or like casing, at least one of said holder terminalshaving a pair of contact engaging elements supported for movementrelatively toward and away from each other, means operable alternativelyto effect movement of said elements relatively apart and to effectretraction of said elements relatively toward each other, and controlmeans for rendering at least a part of the operation of saidalternatively operable means dependent upon operation of a circuit,interrupting means supported by said holder, said control meanscomprising a member slidably mounted on said cover in side by siderelation with said holder and arranged to move automatically from oneposition to another position relative to said holder and cover uponoperation of a circuit interrupting means supported by the holder.

8. A circuit interrupter comprising in combination, a casing havingspaced terminals, a switching unit movably supported on said casing andincluding a cover for the casing and an insulating holder havingautomatically operable circuit interrupting means for electricconnection between said terminals, said unit having spaced terminalscooperative respectively with said casing terminals, at least one of thecasing terminals having a pair of contact members in spaced opposition,the corresponding terminal of said unit having relatively spreadablecontact engaging elements receivable between said contact members,spreader means mounted on said cover and automatically movable from oneposition to another position upon operation or said circuit interruptingmeans, said spreader means when in said one position being operative tomaintain said elements relatively spread apart in firm engagement withsaid contact members, and means operative to effect movement or saidelements relatively toward each other out of engagement with saidcontact members upon movement 01 said spreader means to its said otherposition.

a 9. A circuit interrupter comprising in combination, a casing havingspaced terminals, a switching unit movably supported on said casing andincluding a cover for thecasing and an insulating holder havingautomatically operable circuit interrupting means for electricconnection between said terminals, said unit having spaced terminalscooperative respectively with connection between said terminals, saidunit including also spaced terminals cooperative respectively with saidcasing terminals and a cover for the casing automatically movable fromone position to another position relative to said holder upon operation0! said circuit interrupting said casing terminals, at least one or thecasing terminals having a pair of contact members in spaced opposition,the corresponding terminal of said unit having a pair or contactengaging elements arranged to be received between said contact members,said elements being spreadable apart relative to each other'and beingbiased relatively toward each other, and wedge means slidably mounted onsaid cover and automatically movable from one position to anotherposition upon operation of said circuit interrupting means, said wedgemeans when in said one position being operative to maintain saidelements releasably in flrm engagement respectively with said contactmembers.

10. A circuit interrupter comprising in combination, a casing havingspaced terminals, a switching unit movably mounted on said casing andincluding an insulating holder having automatically operable circuitinterrupting means for means, at least one or said casing terminalshaving contact members in spaced opposition, the corresponding terminalof said unit having contact engaging elements spreadable relativelyapart and. arranged to be received between said contact-members,spreader means operative when said cover is in its said one positionrelative to said holder to maintain said elements relatively spreadapart in firm engagement with said con-. tact members, and meansoperative upon movement of said cover to its said other positionrelative to said holder for effecting retraction of said elements Iromtheir spread apart positions.

11. A circuit interrupter comprising in combination, a casing'havingspaced terminals, a switching unit including a cover for the casing andan insulating holder having automatically operable circuitinterruptingmeans tor connection between said terminals, which saidcover is slidably supported on said holder and is automatically movablefrom one position to another position relative to the holder uponoperation or said interrupting means, hinge means adjacent one end ofsaid holder for pivotally supporting said unit, spaced terminals carriedby said unit for cooperation respectively with said casing terminals, atleast one of the casing terminals having contact members in spacedopposition, the corresponding terminal or said unit having' relativelyspreadable contact engaging elements biased relatively toward each otherand arranged to be received between said contact members. and a wedge onsaid cover operative in BENJAMIN R. MANN".

